Method:
Cook shells according to package directions. Take 6 minutes off of cooking time. Drain well, cool under cold running water, and toss with a minimal amount of olive oil (or cooking spray) to prevent sticking.

Meanwhile, season chicken on both sides with salt and pepper. Cut into small pieces. Heat 3 tbsp olive oil in a large skillet over medium-high heat. Cook chicken until golden brown on both sides. Drain on paper towels.

After 30 minutes, add parsley and basil to sauce, and cook 15 minutes more. Working in batches, purée sauce in blender; return to same pot. (If you have a handblender, you can use it right in the pot). Add cream and simmer 15 minutes. Season to taste with salt and pepper. Set aside.

Preheat oven to 350 degrees F. Spray a large baking pan well with cooking spray. Place a thin layer of sauce in bottom of baking pan.

Stuff shells with chicken mixture. (I find a pastry bag with no tip is ideal for this. If you don't have one, try a demitasse spoon.) Mixture should come to top of shells.

Place shells in baking pan in a single layer. When all shells are filled, cover with sauce. Top with grated provolone, and parsley.

Bake for 20 minutes. Cheese should be golden and sauce should be bubbly. Let sit for 10 minutes before serving.

Note:
You can substitute half-and-half, or evaporated skim milk for the cream.

The cream sauce can be made up to 2 days ahead.

The entire dish can be made ahead of time and frozen (either baked or unbaked). Cover top with plastic wrap then aluminum foil. If unbaked: remove plastic wrap, and re-wrap with foil. Place in a low oven (250 degrees F.) and bake until a knife is easily inserted. Then raise heat to 350 degrees F. And bake as above. If baked: remove plastic wrap and rewrap with foil. Bake at 350 degrees F. until hot.